Image reader incorporated in electro-developing type camera and electro-developing recording medium used therein

ABSTRACT

An electro-developing recording medium has a reference zone exhibiting a substantially-constant transparency to prepare correction data for correcting image pixel signals obtained by an optical and electronic reading of a developed image of the electro-developing recording medium. The reference zone is located at a margin area of an image recording area of the electro-developing recording medium. Further, the reference zone is located adjacent to a side edge of the image recording area of the electro-developing recording medium. The electro-developing recording medium includes an electrostatic information recording medium and an electric charge keeping medium. The electric charge keeping medium has the reference zone exhibiting the substantially-constant transparency. The electric charge keeping medium is formed as a liquid crystal display, and the reference zone can be defined as an empty space from which a portion of a liquid crystal of the liquid crystal display has been eliminated. In the alternative, the reference zone can be defined as a plenum space which is filled with a portion of a liquid crystal of the liquid crystal display, and which is arranged such that an electric field is applied to the plenum space so as to exhibit a constant and maximum transparency.

This is a divisional of application Ser. No. 08/773,138, filed Oct. 16,1996 now U.S. Pat. No. 5,913,077, the contents of which are hereinincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image reader incorporated in anelectro-developing type camera and an electro-developing recordingmedium used therein, in which medium an optical image obtained through aphotographing lens system is electronically and directly recorded anddeveloped as a visible image in a short period of time.

2. Description of the Related Art

The electro-developing recording medium per se is known. For example,Japanese Unexamined Patent Publication No. 5-2280 and U.S. Pat. No.5,424,156 disclose one type of electro-developing recording mediumcomprising an electrostatic information recording medium and an electriccharge keeping (or holding) medium. The electrostatic informationrecording medium includes a photoconducting layer and an inorganic oxidematerial layer, and the electric charge keeping medium includes a liquidcrystal display, both of the mediums being combined to face each otherwith a small gap therebetween.

An electro-developing type camera using the electro-developing recordingmedium is also known, and is referred to as an electro-developing typecamera hereinafter.

In a photographing operation of the electro-developing type camera, avoltage is applied to the electro-developing recording medium. Anoptical image is formed on a light receiving surface of theelectrostatic information recording medium by a photographing opticalsystem, during the application of the voltage to the electro-developingrecording medium. An electric charge distribution is produced over theelectrostatic information recording medium in accordance with a lightintensity distribution of the optical image formed on the lightreceiving surface thereof. Accordingly, the intensity of an electricfield acting on the liquid crystal of the electric charge keeping mediumis in accordance with the electric charge distribution. Thus, theoptical image is reproduced in the electric charge keeping medium as avisible image. Namely, as soon as the optical image is formed on theelectrostatic information recording medium, the optical image isrecorded and developed in the electric charge keeping medium.

Japanese Unexamined Patent Publication No. 5-165005 discloses anothertype of electro-developing recording medium. In this type medium, astructure of the electrostatic information recording medium issubstantially the same as that of the electrostatic informationrecording medium as disclosed in the above-mentioned citations exceptthat the inorganic oxide material layer is omitted therefrom, and thatthe electric charge keeping medium or liquid crystal display is aliquid-crystal-polymer composite (LCPC) using a memory type of liquidcrystal such as smectic liquid crystal. Similar to the first-mentionedtype of electro-developing recording medium, both the electrostaticinformation recording medium and the electric charge keeping medium arecombined to face each other with a small gap therebetween.

Furthermore, Japanese Unexamined Patent Publications No. 6-130347 andNo. 7-13132 disclose yet another type of electro-developing recordingmedium. In this type of medium, the inorganic oxide material layer isalso omitted from the electrostatic information recording medium, andthe electric charge keeping medium or liquid crystal display is also aliquid-crystal-polymer composite (LCPC) using the memory type liquidcrystal. Nevertheless, both the electrostatic information recordingmedium and the electric charge keeping medium are integrally combinedwith each other through the intermediary of a transparent insulatinglayer without any gap therebetween.

When the electric charge keeping medium is a liquid crystal displayusing, for example, a smectic liquid crystal, the developed visibleimage can be kept therein even if the electric field is eliminated fromthe electro-developing recording medium. Thus, the electro-developingrecording medium carrying the developed visible image can be preservedin the same manner as slides or transparency sheet films. Also, in thememory type liquid crystal display, the developed image can be erased byheating it to a given temperature. In this case, the sameelectro-developing recording medium can be repeatedly used forphotographing.

When the electro-developing type camera as mentioned above isconstructed as an electronic still video camera, there is necessarilyprovided an image reader for optically and electronically reading arecorded and developed image of the electro-developing recording medium.

In particular, the image reader may comprise a linear light source, afocussing optical system, and a linear solid image sensor such as aone-dimensional CCD (charge-coupled device) image sensor which arealigned with each other. The electro-developing recording medium isrelatively and intermittently moved with respect to the image readersuch that the electro-developing recording medium passes through a spacebetween the light source and the focussing optical system. Namely, adeveloped image of the electro-developing recording medium is scannedwith light rays emitted from the light source during the relative andintermittent movement of the electro-developing recording medium. Thelight rays passing through the developed image are focussed by thefocussing optical system on alight receiving surface of the solid imagesensor, in which the read image is converted into image pixel signals.

The image pixel signals obtained from the image sensor may be processedin various ways. For example, the read pixel signals may be stored in asecond recording medium such as an IC memory card, a floppy disk, harddisk, or the like. Also, the read image signals may be transferred toform the camera to an external processing device such as a computer, aTV monitor, and so on.

The light source of the image reader may include an LED (light emittingdiode) array, a fluorescent lamp, or the like. As with all types oflight sources, it is impossible to uniformly illuminate the developedimage of the electro-developing recording medium, due to a shading ofthe light source. Accordingly, the image pixel signals obtained from theimage sensor must be subjected to a shading correction in accordancewith shading characteristics of the light source.

Also, as is well known, the solid image sensor of the image readerincludes a plurality of photoelectric-conversion elements such asphotodiodes, but these individual elements exhibit differentphotoelectric-conversion characteristics. Accordingly, the image pixelsignals obtained from the image sensor should be further corrected inaccordance with the different characteristics of thephotoelectric-conversion elements of the image sensor.

Furthermore, individual products of the electro-developing recordingmedium as mentioned above exhibit different transparencycharacteristics. In particular, a transparency characteristic of theelectrostatic information recording medium and a transparencycharacteristic of the electric charge keeping medium varies among theindividual products of the electro-developing recording medium.Accordingly, the image pixel signals obtained from the image sensor mustbe corrected in accordance with the different characteristics of theproducts of the electro-developing recording medium.

Before the corrections mentioned above can be properly carried out,correction data must be prepared on the basis of an actual measurementof the shading characteristic of the light source, the differentcharacteristics of the photoelectric-conversion elements of the imagesensor, and the different transparency characteristics of the productsof the electro-developing recording medium.

Nevertheless, the correction data is relative (not absolute) because theshading characteristic of the light source, the differentcharacteristics of the photoelectric-conversion elements of the imagesensor per se, and the different transparency characteristics of theproducts of the electrostatic recording medium are subjected to adeviation not only due to age-deterioration of the light source and theimage sensor, but also due to a change in environmental factors,especially temperature.

Thus, even if a setting of the correction data is previously carriedout, a proper shading correction of the light source, a properphotoelectric-conversion correction of the image sensor, and a propertransparency correction of the electro-developing recording mediumcannot be ensured.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide an imagereader incorporated in an electro-developing type camera and including alight source and an image sensor to optically and electronically read adeveloped image of an electro-developing recording medium, whereincorrection data for a shading correction of the light source, aphotoelectric-conversion correction of the image sensor, and atransparency correction of the electro-developing recording medium canbe prepared a new or revised whenever the reading of the developed imagefrom the electro-developing recording medium is carried out.

Another object of the present invention is to provide anelectro-developing recording medium which enables revision of thecorrection data in the image reader as mentioned above.

In accordance with a first aspect of the present invention, an imagereader is provided for optically and electronically reading a developedimage of an electro-developing recording medium having a reference zoneexhibiting a substantially-constant transparency. The image readercomprises an optical sensor for sensing light rays passing through thereference zone, and for converting the sensed light rays into opticaldata. A preparation device for preparing correction data based on theoptical data, and a correction device for correcting image data, readfrom the developed image of the electro-developing recording medium,based on the correction data, wherein the correction data is revisedwhenever the image data is read from the developed image of theelectro-developing recording medium.

Preferably, the optical sensor is used to optically and electronicallyread the developed image of the electro-developing recording medium. Thereference zone may be located at a leading side edge of an imagerecording area of the electro-developing recording medium in a readingdirection in which the electro-developing recording medium isintermittently moved with respect to the optical sensor during theoptical and electronic reading of the developed image by the opticalsensor.

In accordance with a second aspect to the present invention, an imagereader is provided for optically and electronically reading a developedimage of an electro-developing recording medium having a reference zoneexhibiting a substantially-constant transparency. The reader comprisesan optical sensor for sensing light rays passing through the referencezone, and for converting the sensed light rays into optical data. Acontrol circuit is provided and includes a memory for storing a firstprogram for preparing correction data based on the optical data, and asecond program for correcting image data, read from the developed imageof the electro-developing recording medium, based on the correctiondata. The correction data is revised whenever the image data is readfrom the developed image of the electro-developing recording medium.

Preferably, the optical sensor is used to read the developed image ofthe electro-developing recording medium. The reference zone may belocated at a leading side edge of an image recording area of theelectro-developing recording medium in a reading direction in which theelectro-developing recording medium is intermittently moved with respectto the optical sensor during the optical and electronic reading of thedeveloped image thereof by the optical sensor.

In the first and second aspects of the present invention, theelectro-developing recording medium comprises an electrostaticinformation recording medium and an electric charge keeping medium, andthe reference zone is formed in the electric charge keeping medium whichmay be constructed as a liquid crystal display. The reference zone maybe defined as an empty space from which a portion of a liquid crystal ofthe liquid crystal display is eliminated. Also, the reference zone maybe defined as a plenum space which is filled with a portion of a liquidcrystal of the liquid crystal display, and which is arranged such thatan electric field is applied to the plenum space so as to exhibit aconstant and maximum transparency.

In accordance with a third aspect of the present invention, there isprovided an electro-developing recording medium having a reference zoneexhibiting a substantially-constant transparency to prepare correctiondata for correcting image pixel signals obtained by an optical andelectronic reading of a developed image of the electro-developingrecording medium.

Preferably, the reference zone is located at a margin area of an imagerecording area of the electro-developing recording medium. Morepreferably, the reference zone is located adjacent to a side edge of theimage recording area of the electro-developing recording medium.

In accordance with a fourth aspect of the present invention, anelectro-developing recording medium is provided including anelectrostatic information recording medium and an electric chargekeeping medium, wherein the electric charge keeping medium has areference zone exhibiting a substantially-constant transparency toprepare correction data for correcting image pixel signals obtained byan optical and electronic reading of a developed image of theelectro-developing recording medium.

Preferably, the reference zone is located at a margin area of an imagerecording area of the electric charge keeping medium. More preferably,the reference zone is located adjacent to a side edge of the imagerecording area of the electro-developing recording medium.

In the fourth aspect of the present invention, the electric chargekeeping medium may be formed as a liquid crystal display. In this case,the reference zone may be defined as an empty space from which a portionof a liquid crystal of the liquid crystal display is eliminated. Also,the reference zone may be defined as a plenum space which is field witha portion of a liquid crystal of the liquid crystal display, and whichis arranged such that an electric field is applied to the plenum spaceso as to exhibit a constant and maximum transparency.

BRIEF DESCRIPTION OF THE DRAWINGS

These objects and other objects of the present invention will be betterunderstood from the following description, with reference to theaccompanying drawings in which:

FIG. 1 is a schematic perspective view illustrating anelectro-developing type camera having an image reader according to thepresent invention;

FIG. 2 is a block diagram of the electro-developing type cameraaccording to the present invention;

FIG. 3 is a schematic perspective view showing an image reader accordingto the present invention;

FIG. 4 is a cross sectional view showing a structure of anelectro-developing recording medium used in an conventionalelectro-developing type camera;

FIG. 5 is a cross sectional view showing another structure of anelectro-developing recording medium used in an conventionalelectro-developing type camera;

FIG. 6 is a cross sectional view showing yet another structure of anelectro-developing recording medium used in an conventionalelectro-developing type camera;

FIG. 7 is a cross sectional view showing a structure of a firstembodiment of the electro-developing recording medium used in theelectro-developing type camera according to the present invention;

FIG. 8 is a cross sectional view showing another structure of the firstembodiment of the electro-developing recording medium used in theelectro-developing type camera according to the present invention;

FIG. 9 is a cross sectional view showing yet another structure of thefirst embodiment of the electro-developing recording medium used in theelectro-developing type camera according to the present invention;

FIG. 10 is a part of a flowchart showing a routine for an image readingoperation executed by the image reader according to the presentinvention;

FIG. 11 is the remaining part of the flowchart showing the routine forthe image reading operation executed by the image reader according tothe present invention;

FIG. 12 is an elevation view showing one type of holder for theelectro-developing recording medium according to the present invention;

FIG. 13 is a plan view of the holder shown in FIG. 12;

FIG. 14 is an elevation view showing another type of holder for theelectro-developing recording medium according to the present invention;

FIG. 15 is a plan view of the holder shown in FIG. 14;

FIG. 16 is an elevation view showing yet another type of holder for theelectro-developing recording medium according to the present invention;

FIG. 17 is a plan view of the holder shown in FIG. 16;

FIG. 18 is a cross sectional view showing a structure of a secondembodiment of the electro-developing recording medium used in theelectro-developing type camera according to the present invention;

FIG. 19 is a cross sectional view showing another structure of thesecond embodiment of the electro-developing recording medium used in theelectro-developing type camera according to the present invention; and

FIG. 20 is a cross sectional view showing yet another structure of thesecond embodiment of the electro-developing recording medium used in theelectro-developing type camera according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is an external view of an electro-developing type cameraconstituted as an electronic still video camera and including an imagereader according to the present invention. The camera comprises a camerabody 10 having an elongated slot 12 formed in a side wall thereof, and aholder 13 (FIG. 3) for an electro-developing recording medium RM (FIG.3) is inserted into the slot 12 such that the electro-developingrecording medium RM held therein is positioned and loaded at a givenposition in the camera body 10.

As shown in FIG. 1, a holder-detecting sensor 14 and aholder-positioning sensor 15 are provided on an inner side wall of theslot 12 beside an entrance port thereof. The holder-detecting sensor 14is utilized to detect an insertion of the holder 13 into the slot 12 ofthe camera body 10, and the holder-positioning sensor 15 is utilized toposition the electro-developing recording medium RM held by the holder13 at the given position in the camera body 10.

When viewing the camera body 10 from a front side thereof, aphotographing optical system 16 is provided at an approximately centrallocation on a front surface of the camera body 10, and an electronicflash 17 is disposed on the front surface of the camera body 10 to theright side of and above the photographing optical system 16. A releaseswitch 18 and a photometry sensor 20 are provided on the front, on theopposite side of the photographing optical system 16 relative to theelectronic flash 17.

A view finder 22 is provided centrally on the top surface of the camerabody 10. A scan start switch 24 is provided on the top surface, to oneside of the view finder 22, and a main switch 25 is provided on theother side of the view finder 22. Further, an output terminal connector26 is provided in the side wall of the camera in which the elongatedslot 11 is formed, so that an image signal obtained by the camera can beoutputted to an external recording device.

Note, in FIG. 1, reference numeral 27 indicates a holder ejecting switchfor ejecting and unloading the holder of the electro-developingrecording medium from the camera body 10 through the elongated slot 12thereof.

FIG. 2 shows a block diagram of an embodiment of the electro-developingtype camera according to the present invention. A system control circuit28, which includes a microcomputer or microprocessor, a read-only memory(ROM), and a random-access-memory (RAM), etc., is provided to controlthe electro-developing type camera.

The photographing optical system 16 has a plurality of lens groups and adiaphragm 30 incorporated therein, and the electro-developing recordingmedium RM held in the holder 13 (FIG. 3) is disposed behind thephotographing optical system 16. A quick return mirror 32 is placedbetween the photographing optical system 16 and the electro-developingrecording medium RM, and a shutter 34 is provided between the quickreturn mirror 32 and the electro-developing recording medium RM. Afocussing glass 36 is included in a view finder optical system of theview finder 22 and is disposed above the quick return mirror 32.

The diaphragm 30, the quick return mirror 32 and the shutter 34 aredriven by an iris drive circuit 38, a mirror drive circuit 40, and ashutter drive circuit 42, respectively, and these drive circuits 38, 40,and 42 are controlled by an exposure control circuit 44 which isoperated in accordance with a command signal outputted from the systemcontrol circuit 28.

During an exposure operation, the aperture size defined by the diaphragm30 is adjusted by the iris drive circuit 38 under control of theexposure control circuit 44 based on an output signal of the photometrysensor 20.

The quick return mirror 32 is usually in a down-position (the inclinedposition shown by the solid lines in FIG. 2), and thus light beamspassing through the photographing optical system 16 are directed to theoptical system of the viewfinder 22, so that an object to bephotographed can be observed through the viewfinder 22 by aphotographer. When a photographing operation is executed, the quickreturn mirror 32 is rotated upward by the mirror drive circuit 40 to anup-position (the horizontal position shown by the broken lines in FIG.2), so that the light beams are directed to the shutter 34.

The shutter 34 is normally closed, however, when taking a photograph,and the shutter 34 is open for a predetermined period of time by theshutter drive circuit 42 under control of the exposure control circuit44. Thus, during the photographing operation, the light beams, passingthrough the photographing optical system 16 and an opening area of theshutter 34, is directed to a light receiving surface of theelectro-developing recording medium RM. Namely, by rotating the quickreturn mirror 42 from the down position to the up-position, and byopening the shutter 34, an optical image to be photographed by thephotographing optical system 16 is focussed on the light receivingsurface of the electro-developing recording medium RM.

A voltage is applied to the electro-developing recording medium RM undercontrol of a recording medium drive circuit 46, which is operated inaccordance with a command signal outputted by the system control circuit28. By exposing the electro-developing recording medium RM whileapplying the voltage, the optical image obtained by the photographingoptical system 16 is developed in the electro-developing recordingmedium RM as a visible image.

An image reader 48 is provided in the camera body 10 in the vicinity ofthe electro-developing recording medium RM positioned in the camera body10. The image reader 48 executes a reading operation for electronicallyreading the developed image of the electro-developing recording mediumRM. The image reader 48 is provided with a linear light source 50, afocussing lens system 52, and a line image-sensor 54, all of which arealigned with each other.

In particular, as best shown in FIG. 3, the image reader 48 comprises aU-shaped frame member 55, by which the linear light source 50, thefocussing lens system 52, and the line image-sensor 54 are supported soas to be aligned with each other. The holder 13 is movable between thelinear light source 50 and the focussing lens system 52, and can bestopped such that the electro-developing recording medium RM heldthereby is aligned with the photographing optical system 16 i.e., suchthat a center of the recording medium RM is coincident with an opticalaxis of the photographing optical system 16.

The linear light source 50 is arranged at the front side of the shutter34 and the electro-developing recording medium RM such that it does notinterfere with a formation of the optical image on the light receivingsurface of the electro-developing recording medium RM aligned with thephotographing optical system 16. The linear light source 50 includes,for example, an LED (light emitting diode) array having a plurality oflight emitting diodes aligned with each other, and a collimating lensfor converting the light rays emitted therefrom, into parallel lightrays. These elements are arranged so as to form a linear light emittingsurface. Of course, the linear light source 50 may comprises anothertype of light emitting device such as a fluorescent lamp in place of theLED array.

The focussing lens system 52 and the line sensor 54 are arranged behindthe electro-developing recording medium RM. The line sensor 54 isconstructed as a one-dimensional CCD sensor having for example 2,000pixel elements which form a linear light receiving surface. The parallellight rays emitted from the linear light source 50 are focussed on thelinear light receiving surface of the line sensor 54 by the focussinglens system 52.

As is apparent from FIG. 3, the holder 13 for the electro-developingrecording medium RM is provided with three detective marks M₁, M₂, andM₃ formed thereon or adhered thereto. The detective mark M₁ is arrangedat a predetermined position so as to be detected by the holder-detectingsensor 14, and each of the detective marks M₂ and M₃ are arranged at apredetermined position so as to be detected by the holder-positioningsensor 15.

In the case where both the holder-detecting sensor 14 and theholder-positioning sensor 15 are constructed as an optical sensor, eachof the detective marks M₁, M₂, and M₃ may be formed as alight-reflecting area. Alternatively, if each of the sensors 14 and 15is constructed as a magnetic sensor, each of the detective marks M₁, M₂,and M₃ may be formed as a magnetic area. Of course, it should beunderstood that any type of sensors may be used as long as thecorresponding detective mark can be detected thereby.

The image reader 48 is also provided with a drive mechanism 56 fordriving and moving the holder 13 upon insertion of the holder into theslot 12 of the camera body 10. As shown in FIG. 3, the drive mechanism56 including a drive motor 56 a such as a stepping motor, a servo motor,or the like, and a pinion 56 b mounted on an output shaft of the drivemotor 56 a. The pinion 56 b is engaged with a rack 13 a formed along anlower edge of the holder 13.

Although is not illustrated, a suitable clutch may be interposed betweenthe pinion 56 b and the output shaft of the drive motor 56 a.Accordingly, the drive motor 56 a is only enabled to transmit arotational drive force to the pinion 56 b through the output shaftthereof when the clutch is turned ON. In other words, when the clutch isturned OFF, the pinion 56 b is free to rotate around the output shaft ofthe drive motor 56 a.

The drive motor 56 a of the drive mechanism 56 includes a drive circuitbuilt therein, and the drive circuit outputs drive pluses to the drivemotor 56 a in accordance with a command signal outputted from the systemcontrol circuit 28. Thus, when the rack 13 a of the holder 13 is engagedwith the pinion 56 b, and when the above-mentioned clutch is turned ON,it is possible to move the holder 13 by driving the drive motor 56 a.

As stated hereinafter in detail, the drive mechanism 56 has twofunctions. One of the two functions is to position the holder 13,manually inserted in the slot 12 of the camera body 10, at aphotographing position, such that an optical image obtained by theoptical system 16 can be formed on the light-receiving surface of therecording medium RM at a proper location during an photographingoperation. The other function is to intermittently move the holder 13step by 50 that a developed image of the electro-developing recordingmedium RM is scanned with light rays emitted from the light source 50,so an image-reading operation for optically and electronically readingthe developed image of the recording medium RM can be carried out.

Note, in FIG. 2, although the holder 13 is shown as moveable in anupward and downward direction, it should be understood that the holder13 is actually moved into and out of the paper with respect to theviewer of FIG. 2.

During the scanning operation or image-reading operation of thedeveloped image from the electro-developing recording medium RM, theshutter 34 is opened, and the linear light source 50 is turned ON. Thelight rays passing through the recording medium RM, i.e., the light rayscarrying image information of the developed image thereof, are focussedon the linear light receiving surface of the line sensor 54 by thefocussing lens system 52. The line sensor 54 serves as aphotoelectric-conversion device for sensing and converting the imageinformation into electrical pixel signals. Of course, the light source50 and the line sensor 54 are of suitable length to completely cover andextended over a width of a recording area of the recording medium RM.The electrical pixel signals are read out from the line sensor 54 duringa movement of the holder 13 between the two adjacent scanning steps.

Control of the light source 50 (i.e., turning the light on and off) iscarried out by a light source drive circuit 58. The reading-out of thepixel signals from the line sensor 54 is controlled by a line sensordrive circuit 60. These drive circuits 58 and 60 are controlled by thesystem control circuit 28.

The pixel signals sensed by, and read out from the line sensor 54 areamplified by an amplifier 62, and are then converted to digital pixelsignals by an analog-to-digital (A/D) converter 64. The digital pixelsignals are subjected to a gamma correction, and so on by an imageprocessing circuit 66 under control of the system control circuit 28,and are then temporarily stored in a memory 68. The memory 68 may havecapacity for storing, for example, a single-frame of digital pixelsignals obtained by a completion of the image-reading operation.

The pixel signals outputted from the memory 68 may be optionallyinputted into an interface circuit 70 through the image processingcircuit 66. In this case, the pixel signals are subjected to a givenprocess such as a format-conversion process and so on, and are thentransferred from the interface circuit 70 to, for example, an externalmonitor device (not shown) through the output terminal connector 26.

Also, the pixel signals outputted from the image process circuit 66 maybe recorded on, for example, a second recording medium, such as an ICmemory card, a floopy disk, a detachable hard disk, or the like, in animage recording (or processing) device 74 therefor. The pixel signalsread out of the second recording medium may be transferred to anexternal processing device such as a personal computer, if necessary. Inthis case, the pixel signals are subjected to a given process such as animage-compression processing, a format-conversion processing in arecording device control circuit 72, and so on.

The interface circuit 70 and the recording device control circuit 72 areoperated in accordance with command signals outputted from the systemcontrol circuit 28.

As shown in FIG. 2, the holder-detecting sensor 14 and theholder-positioning sensor 15 are connected to the system control circuit28, and each of these sensors outputs a detecting signal to the controlcircuit 28 when the corresponding detective mark (M₁, M₂, or M₃) isdetected. Also, the release switch 18 and the scan start switch 24 areconnected to the system control circuit 28, and the photographingoperation and the image-reading operation are carried out by turning theswitches ON, respectively.

Further, the main switch 25 is connected to the system control circuit28 to control ON and OFF settings of a main power source (not shown).Also, the holder-discharging switch 27 is connected to system controlcircuit 28, and the drive motor 56 a is driven in reverse whenever theswitch 27 is turned ON, whereby the holder 13 is discharged from theslot 12 of the camera body 10.

Furthermore, the electronic flash 17 is connected to the system controlcircuit 28 through an electronic flash drive circuit 76, which isassociated with a flash-mode-selection switch (not shown). When a flashmode is selected by the flash-mode selection switch, the electronicflash drive circuit 76 is electrically charged. Then, when the releaseswitch 18 is turned ON for photographing, the electronic flash 17 iselectrically energized by the drive circuit 76.

FIG. 4 shows a structure of one type of the electro-developing recordingmedium RM which can be used in an electro-developing type camera. Thistype of recording-medium RM is identical with that disclosed in JapaneseUnexamined Patent Publication No. 5-2280 and U.S. Pat. No. 5,424,156,the disclosures of which are expressly incorporated herein by referencein their entireties. The electro-developing recording medium RMcomprises an electrostatic information recording medium 78 and anelectric charge keeping medium 80, and a voltage is applied therebetweenby an electric power source 82, illustrated symbolically in FIG. 3.

The electrostatic information according medium 78 is formed bylaminating a base plate 78 a, an electrode layer 78 b, an inorganicoxide material layer 78 c and a photoconducting layer 78 d. Thephotoconducting layer 78 d is formed by laminating an electric chargegenerating layer 78 d ₁ and an electric charge transferring layer 78 d₂.

The electric charge keeping medium 80 is constituted as a liquid crystaldisplay which includes a liquid crystal supporting plate 80 a, a liquidcrystal electrode layer 80 b, and a liquid crystal 80 c intervenedtherebetween. Namely, the liquid crystal 80 c is confined as a film-likelayer between the supporting plate 80 a and the electrode layer 80 b.

In the example of the electro-developing recording medium RM shown inFIG. 4, the electric charge transferring layer 78 d ₂ of thephotoconducting layer 78 d and the liquid crystal supporting plate 80 aof the electric charge keeping medium 80 face each other with a smallgap therebetween. As is apparent from FIG. 4, the whole structure of theelectrostatic information recording medium 78 is transparent.

During photographing, the voltage signal is applied as an recordingmedium activating signal from the electric power source 82 to theelectro-developing recording medium RM, i.e., between the electrodelayer 78 b of the electrostatic information recording medium 78 and theliquid crystal electrode layer 80 b of the electric charge keepingmedium 80. When an optical image is formed on the electrostaticinformation recording medium 78 by the photographing optical system 12during the application of the voltage from the electric power source 82thereto, an electric charge distribution is produced over theelectrostatic information recording medium 78. The electric chargedistribution is formed in accordance with a light intensity distributionof the optical image formed thereon, so that the intensity of anelectric field, acting on the liquid crystal 80 c of the electric chargekeeping medium 80, is in accordance with the electric chargedistribution.

Thus, the optical image obtained from the photographing optical system12 is reproduced in the liquid crystal 80 c as a visible image. Namely,as the optical image is formed on the electrostatic informationrecording medium 78, the image is developed in the electric chargekeeping medium 80.

As is already stated hereinbefore, when the liquid crystal 80 c is of amemory-type, such as smectic liquid crystal, the developed image can bekept in the electro-developing recording medium RM even if the electricfield is eliminated therefrom.

FIG. 5 shows a structure of another type of electro-developing recordingmedium RM which can be used in an electro-developing type camera. Thistype of recording medium RM is identical with that disclosed in JapaneseUnexamined Patent Publication No. 5-165005, the disclosure of which isexpressly incorporated herein by reference in the entirety. In thisdrawing, the same references as used in FIG. 4 represent the sameelements. The structure of the electrostatic information recordingmedium 78 is substantially identical with that shown in FIG. 4 exceptthat the inorganic oxide layer 78 c is omitted therefrom.

In FIG. 5, the electric charge keeping medium or liquid crystal display80 is constituted as a liquid-crystal-polymer composite (LCPC) asdisclosed in the above-mentioned publication. In particular, theliquid-crystal-polymer composite includes a polymer film having aplurality of spherical fine polymer elements dispersed over a surfacethereof, and the polymer film is combined with the liquid crystalelectrode 80 b such that the spherical fine polymer elements areintervened therebetween, and supported on a transparent support plate 80d, such that a memory type of liquid crystal such as smectic liquidcrystal is encapsulated in the space therebetween. Accordingly, once anoptical image is developed in the electro-developing recording mediumRM, the developed image can be kept in the electro-developing recordingmedium RM even if the electric field is eliminated therefrom.

FIG. 6 shows a structure of yet another type of electro-developingrecording medium RM which can be used in an electro-developing typecamera. In this drawing, the same references as used in FIG. 4 representthe same elements. Similar to the case of FIG. 5, the structure of theelectrostatic information recording medium 78 is substantially identicalwith that shown in FIG. 3 except that the inorganic oxide layer 78 c isomitted therefrom. Further, similar to the case of FIG. 5, the electriccharge keeping medium or liquid crystal display 80 is constituted as theliquid-crystal-polymer composite (LCPC).

The electro-developing recording medium RM shown FIG. 6 is substantiallythe same as that of FIG. 5 except that the electrostatic informationrecording medium 78 and the electric charge keeping medium or liquidcrystal display 80 are integrally combined with each other through theintermediary of an transparent insulating layer 83 without any gaptherebetween.

FIG. 7 shows a structure of a first embodiment of the electro-developingrecording medium RM used the electro-developing type camera according tothe present invention, and this recording medium RM is derived from thatof FIG. 4. Note, in FIG. 7, the same references used in FIG. 4 are usedto represents similar elements.

As is apparent from FIG. 7, this electro-developing recording medium RMis the same as that of FIG. 4 except that the electric charge keepingmedium or liquid crystal display 80 is formed with a reference zone 84defined in a part of a margin area thereof. The reference zone 84 isutilized to prepare correction data for a shading correction of thelight source 50, a photoelectric-conversion correction of the lineimage-sensor 54, and a transparency correction of the electro-developingrecording medium RM. In this embodiment, the reference zone 84 isdefined as an empty space from which a portion of the liquid crystal 80c is eliminated.

As is apparent from FIG. 3, the empty space or reference zone 84 islaterally extended to cover the width of the recording area of theelectro-developing recording medium RM. Accordingly, when the referencezone 84 is in alignment with the linear light source 50, as shown inFIG. 3, the light rays emitted therefrom are transmitted through thereference zone 84, and are made incident upon the linear light receivingsurface of the line image-sensor 54 by the focussing lens system 52.

The correction data for the shading correction of the light source 50,the photoelectric-conversion correction of the line image-sensor 54, andthe transparency correction of the electro-developing recording mediumRM shown in FIG. 7, which is prepared on the basis of the light rayspassing through the reference zone 84, exhibits a high reliability,because the reference zone 84 of the electro-developing recording mediumRM has a constant and invariable transparency due to the elimination ofthe liquid crystal therefrom.

FIG. 8 shows another structure of the first embodiment of theelectro-developing recording medium RM used in the electro-developingtype camera according to the present invention, and this recordingmedium RM is derived from that of FIG. 5. Note, in FIG. 8, the samereferences as used in FIG. 4 represents the same elements.

As is apparent from FIG. 8, this electro-developing recording medium RMis the same as that of FIG. 5 except that the electric charge keepingmedium or liquid crystal display 80 is formed with a reference zone 84defined in a part of a margin area thereof. Similar to the case of FIG.7, the reference zone 84 is utilized to prepare correction data for ashading correction of the light source 50, a photoelectric-conversioncorrection of the line image-sensor 54, and a transparency correction ofthe electro-developing recording medium RM.

Also, similar to the structure of FIG. 7, the reference zone 84 isdefined as an empty space from which a portion of the liquid crystal 80c is eliminated, and the empty space or reference zone 84 is laterallyextended to cover the width of the recording area of theelectro-developing recording medium RM. Accordingly, when the referencezone 84 is in alignment with the linear light source 50, as shown inFIG. 3, the light rays emitted therefrom are transmitted through thereference zone 84, and are made incident upon the linear light receivingsurface of the line image-sensor 54 by the focussing lens system 52.

Further, similar to the structure of FIG. 7, the correction data for theshading correction of the light source 50, the photoelectric-conversioncorrection of the line image-sensor 54, and the transparency correctionof the electro-developing recording medium RM, which is prepared on thebasis of the light rays passing through the reference zone 84, exhibitsa high reliability, because the reference zone 84 of theelectro-developing recording medium RM shown in FIG. 8 has a constantand invariable transparency due to the elimination of the liquid crystaltherefrom.

FIG. 9 shows yet another structure of the first embodiment of theelectro-developing recording medium RM used in the electro-developingtype camera according to the present invention, and this recordingmedium RM is derived from that of FIG. 6. Note, in FIG. 9, the samereference used in FIG. 4 are used to represent similar elements.

As is apparent from FIG. 9, this electro-developing recording medium RMis the same as that of FIG. 6 except that the electric charge keepingmedium or liquid crystal display 80 is formed with a reference zone 84defined in a part of a margin area thereof. Similar to the case of FIG.7, the reference zone 84 is utilized to prepare correction data for ashading correction of the light source 50, a photoelectric-conversioncorrection of the line image-sensor 54, and a transparency correction ofthe electro-developing recording medium RM.

Also similar to the structure of FIG. 7, the reference zone 84 isdefined as an empty space from which a portion of the liquid crystal 80c is eliminated, and the empty space or reference zone 84 is laterallyextended to cover the width of the recording area of theelectro-developing recording medium RM. Accordingly, when the referencezone 84 is in alignment with the linear light source 50, as shown inFIG. 3, the light rays emitted therefrom are transmitted through thereference zone 84, and are made incident upon the linear light receivingsurface of the line image-sensor 54 by the focussing lens system 52.

Further, similar to the structure of FIG. 7, the correction data for theshading correction of the light source 50, the photoelectric-conversioncorrection of the line image-sensor 54, and the transparency correctionof the electro-developing recording medium RM, which is prepared on thebasis of the light rays passing through the reference zone 84, exhibitsa high reliability, because the reference zone 84 of theelectro-developing recording medium RM shown in FIG. 9 has a constantand invariable transparency due to the elimination of the liquid crystaltherefrom.

A photographing operation of the electro-developing type camera asmentioned above will be now explained below.

First, the main switch 25 is turned ON, and then the holder 13 for theelectro-developing recording medium RM is manually inserted into thecamera body 10 through the slot 12 thereof. Just after the insertion ofthe holder 13 into the slot 12, the rack 13 a of the holder 13 isengaged with the pinion 56 b of the driving mechanism 56, and thedetective mark M₁ is detected by the holder-detecting sensor 14. Theengagement of the rack 13 a with the pinion 56 b can be smoothly carriedout because the clutch between the output shaft of the motor 65 a andthe pinion 56 b is turned OFF. As soon as the detection of the detectivemark M₁ by the holder-detecting sensor 14 is performed, the clutch isturned ON, and the drive motor 56 a is driven forward to bring theholder 13 into the camera body 10.

Then, when the detective mark M₂ is detected by the holder-positioningsensor 15, the drive motor 56 a of the drive mechanism 56 is stopped sothat the electro-developing recording medium RM is in alignment with thephotographing optical system 16. Namely, the recording medium RM ispositioned at the photographing position. Thus, it is possible to carryout the photographing operation by turning the release switch 18 ON.

When the release switch 18 is turned ON, an output signal of thephotometry sensor 20, i.e., a photometry value is sensed and fetched bythe system control circuit 28, and an exposure calculation is started onthe basis of the fetched photometry value. After a predetermined periodof time has elapsed from the ON operation of the release switch 18, therecording medium activating signal is outputted from the recordingmedium drive circuit 46 to the electro-developing recording medium RM.Namely, the activating voltage is applied between the electrostaticinformation recording medium 78 and the electric charge keeping medium80. Then, when the exposure calculation is completed, the sequenceprocedures necessary for photographing are carried out on the basis ofthe calculated result.

In particular, the aperture size of the diaphragm 30 is adjusted inaccordance with the calculated result. Note, since the diaphragm 30initially has a fully-opened aperture size, the adjustment of thediaphragm 30 is performed such that the diaphragm 30 is adjusted fromthe fully-opened aperture size to a smaller size. Then, the quick returnmirror 32 is moved from the down-positioned (acid lines) to theup-position (broken lines). When it is confirmed that the adjustment ofthe diaphragm 30 and the movement of the quick return mirror 32 from thedown-position to the up position are completed, the shutter 34 isopened, whereby an optical image is focussed and formed on the lightreceiving surface of the electro-developing recording medium RM.

When an exposure period of time, which is determined by the calculatedresult, has elapsed, i.e., when a given exposure is completed, theshutter 34 is closed. Then, the quick return mirror 32 is returned fromthe up-position to the down-position, and the aperture size of thediaphragm 30 is returned to the fully-open area. Successively, theoutput of the recording medium activating signal is stopped. Thus, theoptical image obtained by the photographing optical system 16 isrecorded and developed in the electric charge keeping medium or liquidcrystal display 80.

The developed recording medium RM may be removed from the camera body 10by turning the holder-ejecting switch 27 ON, if necessary. Namely, theholder-ejecting switch 27 is turned ON, the drive motor 56 a isreversely driven for a predetermined period of time, and the clutchbetween the output shaft of the drive motor 56 a and the pinion 56 b isturned OFF. At this time, a part of the holder 13 is ejected from theslot 12 of the camera body 10, and thus the holder 13 can be pulled outof the camera body 10 through the slot 12 thereof by pinching theprojected part with two fingers of a user.

On the other hand, after the photographing operation, the developedimage of the electro-developing recording medium RM may be immediatelyread by actuating the image reader 48. This image-reading operation iscarried out by turning the scan start switch 24 ON, and a preparation ofcorrection data for a shading correction of the light source 50, aphotoelectric-conversion correction of the line image-sensor 54, and atransparency correction of the electro-developing recording medium RMtakes place in the image-reading operation.

FIGS. 10 and 11 show a flowchart for explaining the image-readingroutine for optically and electronically reading the developed image ofthe electro-developing recording medium RM. This routine is executedwhenever the scan start switch 24 is turned ON.

At step 1001, the light source 50 is turned ON by the light source drivecircuit 58. Then, at step 1002, the shutter 34 is opened by the shutterdrive circuit 42.

At step 1003, the drive motor 56 a is driven a forward direction so thatthe holder 13 is further moved toward the inside of the camera body 10.At step 1004, it is determined whether the detective mark M₃ is detectedby the holder-positioning sensor 15.

When the mark M₃ is detected by the holder-positioning sensor 15, i.e.,when the empty space or reference zone 84 of the electro-developingrecording medium RM is aligned with the linear light source 50, as shownin FIG. 4, the routine proceeds from step 1004 to step 1005, in whichthe drive motor 56 a is stopped. Thus, the light rays emitting from thelight source 50 and passing through the reference zone 84 are madeincident upon the light receiving surface of the line image-sensor 54(having, for example 2,000 pixel elements) by the focussing lens system52.

At step 1006, an address counter “N” is reset. Then, at step 1007, 2,000pixel signals corresponding to the number of pixel elements of the lineimage-sensor 54 are read out therefrom in accordance with shift clocksignals outputted from the line sensor drive circuit 60 to the lineimage-sensor 54. Of course, the 2,000 pixel signals represent a shadingcharacteristic of the light source 50 and photoelectric-conversioncharacteristics of the pixel elements of the line image-sensor 54. Therespective 2,000 pixel signals are successively amplified by theamplifier 62, and are then converted into digital pixel data L_(N)(N=0˜1,999) by the A/D converter 64. Thereafter, the digital pixel dataL_(N) is received and fetched by the system control circuit 28 throughthe image processing circuit 66.

At step 1008, the following calculation is executed:

k_(N)→1/L_(N)

Namely, the reciprocal of the digital pixel data L_(N) is calculated andprepared as correction data k_(N). Then, at step 1009, the calculatedcorrection data k_(N) is temporarily stored in the RAM of the systemcontrol circuit 28.

At step 1010, the address counter N is incremented by “1”. Then, at step1011, it is determined whether or not the address counter N has reached“1,999”, i.e., it is determined whether the preparation of thecorrection data k_(N) is completed with respect to all of the 2,000pixel elements of the line image-sensor 54. If N<1,999, the routinereturns from step 1011 to step 1008.

At step 1011, when the address counter N has reached 1,999, i.e., whenthe preparation of the correction data k_(N) is completed, the routineproceeds from step 1011 to step 1012, in which the drive motor 56 a isreversely driven until the electro-developing recording medium RM heldby the holder 13 is positioned at a scan start position at which theimage reading operation is started by the image reader 48. Note, thepositioning of the recording medium RM at the scan start position may becontrolled by counting a number of drive pulses for driving the drivemotor 56 a.

At step 1013, the address counter is reset. Then, at step 1014, 2,000image-pixel signals corresponding to the number of pixel elements of theline image-sensor 54 are read out therefrom in accordance with the shiftclock signals outputted from the line sensor drive circuit 60 to theline image-sensor 54. Of course, the 2,000 image-pixel signals arederived from the light rays passing through the developed image of theelectro-developing recording medium RM and carrying the imageinformation thereof. The respective 2,000 image-pixel signals aresuccessively amplified by the amplifier 62, and are then converted intodigital image-pixel data I_(N) (N=0˜1,999) by the A/D converter 64.Thereafter, the digital image-pixel data I_(N) are received and fetchedby the system control circuit 28 through the image processing circuit66.

At step 1015, the following calculation is executed:

AI_(N)←I_(N)×k_(N)

Namely, the digital image-pixel data I_(N) is multiplied by thecorresponding correction data k_(N), and the product or correcteddigital image-pixel data AI_(N) is obtained.

At step 1016, the corrected digital image-pixel data AI_(N) is subjectedto a gamma correction, and so on by an image processing circuit 66, andis then temporarily stored in a memory 68. Then, at step 1017, theprocessed digital image-pixel data AI_(N) is stored in the memory 68.

At step 1018, the address counter N is incremented by “1”. Then, at step1019, it is determined whether the address counter N has reached“1,999”, i.e., it is determined whether all of the digital image-pixeldata I_(N) is corrected and processed. If N<1,999, the routine returnsfrom step 1019 to step 1015.

At step 1019, when the address counter N has reached 1,999, i.e., whenthe correction and processing of the digital image-pixel data I_(N) arecompleted, the routine proceeds from step 1019 to step 1020, in whichstep 1011 to step 1022, in which the drive motor 56 a is reverselydriven such that the holder 13 is intermittently moved by one scanningstep. A pitch of the scanning steps corresponds to a number of scanninglines by which the image reader 48 reads the developed image of theelectro-developing recording medium RM. Note, the intermittent movementof the holder 13 by one scanning step may be controlled by counting anumber of driving pulses for driving the drive motor 56 a.

At step 1021, it is determined whether the developed image of theelectro-developing recording medium RM is completely read by the imagereader 48. If the reading or the developed image is incomplete, theroutine returns from step 1021 to step 1013, and the scanning operationis repeated in the same manner as mentioned above.

At step 1020, it is confirmed that the reading of the developed image ofthe electro-developing recording medium RM is completed, the routineproceeds from step 1021 to step 1022, in which the light source 50 isturned OFF.

FIGS. 12 and 13 show the holder 13 for the electro-developing recordingmedium RM. The insertion of the holder 13 into the slot 12 of the camerabody 10 is carried out in such a manner that the side edge of the holder13, to which the mark M₁ is applied, is defined as a leading side edge.Nevertheless, during the reading operation, the holder 13 isintermittently moved in the reverse direction indicated by an arrow ARin FIGS. 12 and 13. When this intermittent movement direction of theholder 13 is defined as a reading direction, the empty space orreference zone 84 is preferably located at a leading side edge of theimage recording area, indicated by reference ID of theelectro-developing recording medium RM in the reading direction. This isbecause the electro-developing recording medium RM can be promptly movedto the scan start position after the preparation of the correction data.

FIGS. 14 and 15 show another type of holder for the electro-developingrecording medium RM, which is indicated by reference 13′. The holder 13′has an elongated shape, and holds three of the recording media arrangedto be aligned with each other. An electro-developing type camera usingthe holder 13′ is constituted such that the elongated holder 13′ passesthrough the camera body thereof. As illustrated, the holder 13′ has arack 13 a′ formed along the lower edge thereof, and the rack 13 a′ canbe engaged with the pinion 56 b of the drive mechanism 56, whereby theholder 13′ can be moved in the same manner as mentioned above.

As is apparent from FIGS. 14 and 15, during the reading operation, theholder 13′ is intermittently moved in the reading direction as indicatedby the arrow AR. Also, in each of the electro-developing recording mediaRM, the empty space or reference zone 84 is located at the leading sideedge of the image recording area ID of the recording medium RM in thereading direction for the same reasons as mentioned above.

FIGS. 16 and 17 show yet another type of holder for theelectro-developing recording medium RM, which is substantially the sameas shown in FIGS. 14 and 15 except that only one of the three recordingmedia RM has the empty space or reference zone 84. Namely, the referencezone 84 is formed in only one of the recording media RM, which isdefined as a leading medium in the reading direction AR, and thereference zone 84 is also located at the leading side edge of the imagerecording area ID of the recording medium RM concerned in the readingdirection for the same reasons as mentioned above.

In the case of FIGS. 16 and 17, of course, the correction data (k_(N))is prepared on the basis of the light rays passing through the referencezone 84, and are commonly used to correct image data obtained from eachof the recording media RM.

FIG. 18 shows a structure of a second embodiment of theelectro-developing recording medium RM used in the electro-developingtype camera according to the present invention. Similar to the case ofFIG. 7, this type of recording medium RM is also derived from thatdisclosed in Japanese Unexamined Patent Publication No. 5-2280 and U.S.Pat. No. 5,424,156 (FIG. 4). Namely, the electrostatic informationrecording medium 78 and the electric charge keeping medium 80 aresubstantially the same as shown in FIG. 7.

In this second embodiment, the reference zone 84′ is formed as a plenumspace in place of the empty space 84 shown in FIG. 7. In particular, theplenum space or reference zone 84′ is filled with a portion of theliquid crystal 80 c without the elimination of liquid crystal therefrom,and is defined by a transparent electrode segment 80 b′. The transparentelectrode segment 80 b′ is electrically independent from the liquidcrystal electrode layer 80 b. Namely, the transparent electrode segment80 b′ is isolated from the liquid crystal electrode layer 80 b by adielectric material 86 surrounding the segment 80 b′.

As shown in FIG. 18, Whenever the correction data (k_(N)) is prepared, avoltage is applied between the electrode layer 78 b of the electrostaticinformation recording medium and the electrode segment 80 b′ by anelectric power source 88 such that the plenum space or reference zone84′ exhibits a maximum transparency.

Similar to the empty space 84 shown FIG. 7, the plenum space 84′ isformed in a part of a margin area of the electric charge keeping mediumor liquid crystal display 80, and is, of course, utilized to prepare thecorrection data for the shading correction of the light source 50, thephotoelectric-conversion correction of the line image-sensor 54, and thetransparency correction of the electro-developing recording medium RM.Also, the plenum space 84′ is laterally extended to cover the width ofthe recording area of the electro-developing recording medium RM.Accordingly, when the reference zone 84 is in alignment with the linearlight source 50, the light rays emitted therefrom are transmittedthrough the plenum space or reference zone 84′, and are focussed on thelinear light receiving surface of the line image-sensor 54 by thefocussing lens system 52.

The correction data for the shading correction of the light source 50,the photoelectric-conversion correction of the line image-sensor 54, andthe transparency correction of the electro-developing recording mediumRM, which is prepared on the basis of the light rays passing through thereference zone 84′, also exhibits a high reliability, because a constantor invariable transparency of the plenum space or reference zone 84′ canbe ensured due to the application of voltage between the electrode layer78 b and the electrode segment 80 b′. Note, the electro-developingrecording medium RM as shown in FIG. 18 is superior to that of FIG. 7because an age-deterioration of the liquid crystal 80 c is taken intoaccount in the preparation of the correction data.

FIG. 19 shows another structure of the second embodiment of theelectro-developing recording medium RM used in the electro-developingtype camera according to the present invention. Similar to the structureof the FIG. 8, this type of recording medium RM is also derived fromthat disclosed in Japanese Unexamined Patent Publication No. 5-165005(FIG. 5). Namely, the electrostatic information recording medium 78 andthe electric charge keeping medium 80 are substantially the same asshown in FIG. 5. As is apparent from FIG. 19, the plenum space orreference zone 84′ is formed in the electric charge keeping medium orliquid crystal display 80 in the same manner as in the case of FIG. 18.

FIG. 20 shows yet another structure of the second embodiment of theelectro-developing recording medium RM used in the electro-developingtype camera according to the present invention. Similar to the structureof FIG. 9, this type is also derived from that disclosed in JapaneseUnexamined Patent Publications No. 6-130347 and No. 7-13132 (FIG. 6).Namely, the electrostatic information recording medium 78 and theelectric charge keeping medium 80 are substantially the same as shown inFIG. 6. As is apparent from FIG. 20, the plenum space or reference zone84′ is formed in the electric charge keeping medium or liquid crystaldisplay 80 in the same manner as in the case of FIG. 18.

As is apparent from the foregoing, according to the present invention,whenever a reading of a developed image from the electro-developingrecording medium is executed, correction data for a shading correctionof a light source, a photoelectric-conversion correction of an imagesensor, and a transparency correction of the electro-developingrecording medium is freshly prepared and renewed. Accordingly, theshading correction of the light source and the photoelectric-conversioncorrection of the image sensor can be properly and reliably can becarried out.

Finally, it will be understood by those skilled in the art that theforegoing description is of preferred embodiments of the presentinvention, and that various changes and modifications may be made to thepresent invention without departing from the spirit and scope thereof.

The present disclosure relates to subject matter contained in JapanesePatent Applications No. 7-293668 (filed on Oct. 16, 1995) and No.8-134245 (filed on May 1, 1996), which are expressly incorporatedherein, by reference, in their entirety.

What is claimed is:
 1. An electro-developing recording medium having areference zone exhibiting a substantially-constant transparency toprepare correction data for correcting image pixel signals obtained byan optical and electronic reading of a developed image of saidelectro-developing recording medium.
 2. An electro-developing recordingmedium as set forth in claim 1, wherein said reference zone is locatedat a margin area of an image recording area of said electro-developingrecording medium.
 3. An electro-developing recording medium as set forthin claim 2, wherein said reference zone is located adjacent to a sideedge of the image recording area of said electro-developing recordingmedium.
 4. The electro-developing recording medium according to claim 1,said reference zone having a transparency through which light rays canpass.
 5. The electro-developing recording medium according to claim 1,said reference zone being located in an image recording area of saidelectro-developing recording medium at a leasing side edge, in adirection in which said electro-developing recording medium isintermittently moveable with respect to an optical sensor when theoptical sensor reads the image on the electro-developing recordingmedium.
 6. The electro-developing recording medium according to claim 1,said recording medium comprising an electrostatic image recording mediumand an electric charge keeping medium, said reference zone being formedin said electric charge keeping medium.
 7. An electro-developingrecording medium including an electrostatic information recording mediumand an electric charge keeping medium, wherein said electric chargekeeping medium comprises a reference zone exhibiting asubstantially-constant transparency to prepare correction data forcorrecting image pixel signals obtained by an optical and electronicreading of a developed image of said electro-developing recordingmedium.
 8. An electro-developing recording medium as set forth in claim7, wherein said reference zone is located at a margin area of an imagerecording area of said electric charge keeping medium.
 9. Anelectro-developing recording medium as set forth in claim 8, whereinsaid reference zone is located adjacent to a side edge of the imagerecording area of said electro-developing recording medium.
 10. Anelectro-developing recording medium as set forth in claim 7, whereinsaid electric charge keeping medium is formed as a liquid crystaldisplay, and said reference zone is defined as an empty space from whicha portion of a liquid crystal of the liquid crystal display iseliminated.
 11. An electro-developing recording medium as set forth inclaim 7, wherein said electric charge keeping medium is formed as aliquid crystal display, and said reference zone is defined as a plenumspace which is filled with a portion of a liquid crystal of the liquidcrystal display, and which is arranged such that an electric field isapplied to said plenum space so as to exhibit a constant and maximumtransparency.
 12. The electro-developing recording medium according toclaim 7, said reference zone having a transparency through which lightrays can pass.
 13. The electro-developing recording medium according toclaim 7, said reference zone being located in an image recording area ofsaid electro-developing recording medium at a leading side edge, in adirection in which said electro-developing recording medium isintermittently moveable with respect to an optical sensor when theoptical sensor reads the image on the electro-developing recordingmedium.
 14. The electro-developing recording medium according to claim7, said recording medium comprising an electrostatic image recordingmedium and an electric charge keeping medium, said reference zone beingformed in said electric charge keeping medium.